gnulib-tool.py: Correct the result of --extract-dependents

[Bruno Haible]

As mentioned in
<https://lists.gnu.org/archive/html/bug-gnulib/2024-08/msg00018.html>,
$ ./gnulib-tool --extract-dependents hamt
should return
hamt-tests

This patch does it.


2024-08-16  Bruno Haible  <bruno@clisp.org>

        gnulib-tool.py: Correct the result of --extract-dependents.
        * pygnulib/GLModuleSystem.py (GLModule.getDependents): Add the current
        module's test module, if that exists.

diff --git a/pygnulib/GLModuleSystem.py b/pygnulib/GLModuleSystem.py
index 1f758fb0e5..e9855f775c 100644
--- a/pygnulib/GLModuleSystem.py
+++ b/pygnulib/GLModuleSystem.py
@@ -596,6 +596,11 @@ def getDependents(self) -> list[GLModule]:
             listing = [ line
                         for line in listing
                         if self.modulesystem.file_is_module(line) ]
+            # ${module}-tests implicitly depends on ${module}, if both exist.
+            if self.isNonTests():
+                implicit_dependent = self.name+'-tests'
+                if self.modulesystem.exists(implicit_dependent):
+                    listing.append(implicit_dependent)
             candidates = sorted(set(listing))
             result = []
             for name in candidates: